I have them in my WD12. Haven't needed them yet but they are always a good idea.  

   I also have an inflatable bag in the front of my Wood Duck-12, that I haven't needed. But if needed at least it would keep some water out of that large space.

I use a 20 L dry sack in the front of my WD12. It provides dry storage and buoyancy. So far nothing significant has made it past the spray skirt.

Stay dry,

Laszlo

I wedge two Holt Allen Opti flotation bags under the center thwart of my EP when I go out on bigger/rougher water.

   Thanks to all for the advice.   Better safe is the key.